(1) Field Of The Invention
The present invention relates to encapsulating semiconductors and more particularly, to a method of encapsulating semiconductors utilizing an encapsulant matrix hereinafter referred to as a premold, prepared prior to encapsulating a semiconductor and subsequently utilized to achieve semiconductor encapsulation.
(2) Background Art
Semiconductor encapsulation apparatus is very well known to those skilled in the art. In this regard an encapsulation system is known to be marketed by Mesa Technology, Mountain View, California under the trademark "Mesa-Pack". This encapsulation system is arranged to accept semiconductors which have been previously bonded to beam leads attached to a strip of polyimide film, the semiconductor and film strip assembly looking much like photo film with the semiconductor and beam leads located where the picture frames would normally be located. The "Mesa-Pack" system is described in an article entitled "Encapsulated Chip Package on Tape" published in the Aug. 1985 issue of Semiconductor International magazine and is arranged to dispense fluid encapsulant directly onto the semiconductor substrate in either a dot, line or drawn pattern. After dispensing of the encapsulant onto the semiconductor, the encapsulant is cured to form a protective cover over the semiconductor substrate and beam lead bonding sites thereby protecting the semiconductor and bonds from environmental effects.
Another semiconductor encapsulation machine is known to be manufactured by International Micro Industries Incorporated, Cherry Hill, New Jersey and designated model #EM-1166. The EM-1166 encapsulation machine is also arranged to accept semiconductors in the photo film format and to dispense on the semiconductor via dispensing needles a liquid encapsulant. Following dispensing, the encapsulant is prejelled via a heated nitrogen gun and subsequently cured in an infrared oven.
The above encapsulation systems, while representative of the art, are seen to teach methods of encapsulating semiconductors not employing the method of the subject invention.